M 104: The Sombrero Galaxy

Messier 104 (M104), also known as NGC 4594 or the Sombrero Galaxy, was first discovered in 1781 by Pierre Méchain. This striking spiral galaxy is located in the constellation Virgo, approximately 30 million light-years from Earth, with a diameter of about 50,000 light-years. Its distinctive shape, resembling a wide-brimmed sombrero hat, is the reason behind its popular name (*).  

M104 is a peculiar galaxy with an ambiguous classification. A NASA/JPL paper describes it as having characteristics of both a spiral and an elliptical galaxy, stating: "While some galaxies are rotund and others are slender disks like our spiral Milky Way, new observations from NASA's Spitzer Space Telescope show that the Sombrero Galaxy is both..." (**).  

One of M104’s most fascinating features is the presence of a supermassive black hole at its center. Observations suggest that this black hole has a mass of at least one billion times that of the Sun.  

Image and Processing Details  

This is an LRGB image taken with a TOA-150 telescope and an STL-11000M camera (1.69” /pixel), with a total exposure time of approximately 19 hours.  

Processing Notes  

Regarding color calibration, M104 is classified as either an Sa-type spiral or an elliptical galaxy (**). Therefore, the default Average Spiral Galaxy white reference in SpectrophotometricColorCalibration is not the best option for this image. Instead, I used the Sa Galaxy reference.  

Since my goal with this image was to reveal as much detail as possible in the prominent dust and gas ring, I applied:  

a) Drizzle x2 integration for increased resolution (0.84" /pixel), and  

b) A strong HDRMultiscaleTransform application, which enhances the dynamic range. This compression has slightly reduced the (*) "sombrero" effect 😅.  

Click on the image for full resolution versions, or go to the Gallery section for complete exposure details.

Image processing: Pixinsight.

Observatory automation and remote operation with Talon6.